Combined device for measuring insulation, integrity of protective conductors, and TRMS multimeter functions The M72 is primarily designed for measuring insulation resistance and the integrity of protective and equipotential conductors with a 200 mA current in electrical installations, typically private. In addition to these measurements, the M72 offers many additional features such as phase sequence measurement with a single terminal, leakage current measurement using an additional clamp transformer, and a powerful multimeter function for measuring voltage and current in true RMS (TRMS).